Greenhouse Structures Unit
GREENHOUSES
Structures are covered with ______material
Allows ______to enter for plant growth and maintenance
Artificially heated and ______
Greenhouses are used for:
______tender plants
Starting seeds
Starting ______
Raising ______and ______out of season
Growing ______
Designed to local weather extremes
Minimum ______
Max. ______speeds
Max. ______loads
Min. ______transmission
Environmental considerations for plants
Three considerations are: ______, ______, and______.
Headhouse
Office, storage, and work space from which greenhouses are located
Greenhouse Types and Arrangements
Attached Greenhouse
Advantages:
Less ______needed
Can be utilized to ______in winter, cool in summer through heat and humidity change
Con’t
Disadvantages
Existing building can ______the greenhouse, limiting light needed for plants
______and ______are difficult to control.
Types of Attached Greenhouses
Lean-To
Attached to building, usually on the ______facing side
______to the roof is attached to the building side
Attached Even-Span
______is attached to a building
______are equal length
Advantage
More available ______
DISADVANTAGE
More ______to build and ______than a lean-To
Window mounted
Attached to ______as a ______unit.
Disadvantage
______space
Plant environment is ______to control
Types of Freestanding Greenhouses
Even ______
______- span
Quonset
Gothic ______
Even-Span
Rafters of ______length
Usually clears spans w/ ______supports
ADVANTAGE: Allows more ______of space/ movement and ______
Uneven-Span
Rafters of ______length
Usually used for ______placement
ADVANTAGES: maximizes ______
DISAVANTAGES: ______of greenhouse can make working in it difficult
Quonset
______roofs; military hut-style
May or may not include ______
Gothic Arch
______arch-forward style
Eliminates ______supports
Adds a double layer of ______covering
Connected Greenhouses
Advantages
Less ______material
Less ______needed for spacing
______conservative due to less ______
Workers and equipment can move through the buildings rather than between buildings
Disadvantages
Creating different ______conditions for crops is more difficult
Connected houses do not distribute ______weight well and can collapse
Require ______cables to melt snow to prevent ______
Difficult to ______, requires fans to circulate
Types of Connected Greenhouses
Gutter-connected – ______greenhouses connected together
Venlo or Dutch ______greenhouses connected together
Barrel Vault - ______greenhouses connected together
Sawtooth- ______greenhouses connected together
Greenhouse External and Internal Structures and Equipment
Components of Greenhouse Structure
Foundation
Concrete ______
Sidewalls
Frame
______wood
Aluminum
______steel
NOTE: glass greenhouses require more ______support than polyethylene
Foundation
Continuous ______bed upon which ______is built
Water and electrical lines are ______before concrete is poured
Concrete Footings
______supports located below the______line (cannot be affected by frost heaves)
May Take the place of ______
Sidewalls
Between the ______and ______
Greenhouse Coverings
Glass
Provides ______light ______
______-lasting.
Double-strength, grade B weight used for greenhouses except in cold areas, where thermopane (with a ¼ to ½ inch layer of trapped air between panes) is used.
Expensive ______and heating.
Requires good structural support of aluminum or steel.
Polycarbonate
______
Ease of installation.
Good ______insulation.
Good ______transmission.
Available in clear, corrugated single layer panels.
Good replacement for ______fiberglass-reinforced plastic.
Disadvantage:______
Corrugated Fiberglass-Reinforced Plastic
______in cost.
Ease of installation.
______strength.
______lifespan.
Good light ______
Can ______over time from ______damage, dust, and pollutants.
Flammable and may increase insurance costs.
Polyethylene
______installation.
______heating cost.
______
UV ______increase its lifespan.
Produces ______which increases wet plant foliage and ______possibilities.
Light reduction compared to glass.
Acrylic
______to install
Good heat ______.
Good ______transmission.
______lifespan.
Flammable.
HEATING
Steam
-produced in a ______
-Circulated by pipes in sidewalls and overhead
-Used mostly when several greenhouses are ______
Hot water
-similar to ______but used in smaller houses
Air
-Local Units force ______into houses
-Can be moved through ______overhead tubing
Radiant
-Individual unit heaters
-Directly ______the plants in the greenhouse
Solar
Restricted to passive designs
Crops require little ______heat
Unit Heaters
Fired by ______gas, propane, ______, coal, or wood.
______not recommended, due to reliability.
Determining size HVAC
______
Area of exposed greenhouse surface
Type of ______and materials
= # of ______need maintain inside temp.
Cooling
Fan and Pad
______fan draws air through moist cellulose pad.
Air is cooled through ______
For low ______conditions
Fog evaporative
______is generated within the greenhouse
Heat is ______by the water droplets and evaporated, cooling the greenhouse ______.
Used in ______houses
Ventilation
Natural
Air exchange is fostered through open ridge and side ______, under ______control.
Not advised for ______cooling due to possible ______injury
Fan-Tube
Fans bring in ______air which is mixed with ______air and distributed though holes in ______tubing running the length of the greenhouse
May be used in conjunction with heating systems
Shading
Fabric
Black ______pulled over the greenhouse to ______light intensity and temperature.
Comes in a range of ______percentages.
Compound
______compounds applied to glass or polyethylene covered greenhouses to reduce light intensity and temperature
Forcing Structures Used in Raising Plants
Lath House/ Shade House
Provides ______shade and ______protection for plants
Allows ______and air to ______structure
Used as an ______setting for plants with some protection
Much smaller than a greenhouse
For plant establishment, ______, or plants requiring shade
______wood or ______steel
Frame is three sided: roof, back, two sides
Covering
Wooden roof is slatted to permit weather and light, but not full sunlight
Plastic net fabric is commonly used, in a range of shade percentages
Overwintering Structures
Cold Frame
______Structures
______protection and moderated ______control
Placed partially below ground level
Frame is wood W/ hinged or sliding glass top opening or covering of plastic film
Backs are higher and tops slanted down for weather protection
______can be used on tops of plants or containers
Hotbed
Similar to a ______in structure, but with and underlying heat source
Used to start ______or ______
Heat from ______(steam or hot water), ______(electricity), or ______are used (manure)
Hotbeds have ______or ______sides and back with a glass top slide or hinged covering
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Floriculture & Greenhouse – Structures Unit